The yield of experimental yeast populations declines during selection

Abstract

The trade-off between growth rate and yield can limit population productivity. Here we tested for this lifehistory trade-off in replicate haploid and diploid populations of Saccharomyces cerevisiae propagated in glucose-limited medium in batch cultures for 5000 generations. The yield of single clones isolated from the haploid lineages, measured as both optical and population density at the end of a growth cycle, declined during selection and was negatively correlated with growth rate. Initially, diploid populations did not pay this cost of adaptation but haploidized after about 1000 -3000 generations of selection, and this ploidy transition was associated with a decline in yield caused by reduced cell size. These results demonstrate the experimental evolution of a trade-off between growth rate and yield, caused by antagonistic pleiotropy, during adaptation in haploids and after an adaptive transition from diploidy to haploidy.

Trade-offs between microbial growth phases lead to frequency-dependent and non-transitive selection

“…Correlations between growth rate and yield have long been the focus of r/K selection studies; some of these experiments have indeed found tradeoffs between growth rate and yield [15][16][17]44], but others have found no tradeoff, or even a positive correlation [5-7, 12, 13]. Measurements of lag times have also found mixed results [6,11,41,42,46].…”

“…2B,C), as commonly considered in r/K selection studies [5,7,[12][13][14][15][16][17]. If the mutant has a longer lag time, then having a higher yield will be advantageous since the greater resource efficiency gives the mutant more time to grow exponentially to make up for its late start (Fig.…”

“…Previous work has focused mainly on the possibility of tradeoffs between these traits, especially between exponential growth rate and yield (resource efficiency) in the context of r/K selection [5,7,[12][13][14][15][16][17], as well as between growth rates at low and high concentrations of * To whom correspondence should be addressed.…”

Availability of public goods shapes the evolution of competing metabolic strategies

“…A lthough the existence of tradeoffs in evolution seems to be undisputable, experimental evidence obtained under controlled conditions is scarce. Several examples failed to show tradeoffs (1)(2)(3)(4), whereas others could find them (5,6) or found general but not universal tradeoffs (7,8). A tradeoff between growth rate and growth yield in microbes (9-11) has direct implications for experiments carried out in liquid cultures.…”

“…This is especially of importance during prolonged cultivations such as laboratory evolution experiments. In suspension, fast-growing variants outcompete slower growing ones at the cost of biomass yield (5). The yield versus rate optimization is governed by a dilemma where fast growth is advantageous from the perspective of an individual cell, whereas slow growth, and therefore high yield, is advantageous from the perspective of a population.…”